Staircase slide



FIG. 1 is a perspective view of a staircase slide.

FIG. 2 is a right side view of the staircase slide of which the left side is a mirror image.

FIG. 3 is a front view of the staircase slide; and,

FIG. 4 is a front-end view of the staircase slide.

The rear view and bottom view are omitted and form no part of the claimed design.

The broken line showing of the steps and railing is included for the purpose of illustrating and forms no part of the claimed design. 

CLAIM The ornamental design for a staircase slide, as shown and described. 